Apparatus for simulating free fall through air



Dec. 23, 1969 4` RQH. NORHE'IM, JR i 3,484,953

APPARATUS FOR SIMULATING FREE FALL THROUGH AIR Filed May 15. 1967 Afromeys United States Patent Office 3,484,953 Patented Dec. 23, 1969 3,484,953 APPARATUS FOR SIMULATING FREE FALL THROUGH AIR Ray H. Norheim, Jr., 96 Linda Ave., Oakland, Calif. 94611 Filed May 15, 1967, Ser. No. 638,318 Int. Cl. G09b 15/06; A63 15/12 U.S. Cl. 35-29 8 Claims ABSTRACT OF THE DISCLOSURE The invention relates to apparatus for simulating free fall through air of a person. The invention may be used for an amusement or for training jumpers and acquainting them with the feeling and sensation of free fall through air. In either applicatiomthe person is subjected to a sensation akin to that experienced when pumping from an airplane without opening his parachute.

According to the instant process, the person using the apparatus can be gradually familiarized with the conditions likely to `be encountered in free fall through the atmosphere and can, by manipulation of his limbs or by holding objects such as a loose portion of his clothing or a special sail or small parachute in certain positions, control his motion relatively to the air and learn by experience what effect these operations would have in actual free fall. Also, he can gain some familiarity with the effects on his body of being supported solely by air.

In summary, according to the invention air is flowed upwards through a duct with a velocity approximately the terminal velocity of free fall of the person through still air as the person enters the duct. In the preferred embodiment the duct is vertically elongated andthe person enters the duct through an upper access opening and leaves it through a lower access opening, the duct being provided with lguard means above the upper and below the lower access opening to limit his yextent of vertical movement. The guard means are preferably open-mesh nets, e.g., made of nylon cord, through which the air current flows.

The invention will be further described with reference to the accompanying drawing forming a part of this specification, the single view of which is a vertical sectional view through an illustrative embodiment of the apparatus.

,Referring to the drawing, the apparatus includes a vertical duct 1 having lower and upper guard screens 2 and 3 extending across the duct. The duct may, for example, have a height of 20 to 50 feet between the screens, and may have its walls of metal or other material, such as plyboard and may be at least in part of transparent material, such as plexiglass. The screens have openings for the passage of air and are preferably yieldable, to check the vertical movement of a person with a cushioning effect. For example, the screens may be open-mesh nets of elastic material such as 600 lb. test nylon cord (about l inch), and the lower screen 2 may have openings three to four inches square or in diameter while the upper screen 3 may be the same or have larger openings, e.g.,

about ten inches square or in diameter. Air is supplied to the lower end of the duct by any suitable means, such as one or more adjustable or controllable pitch propellers 4 and 5 and driven by an electric motor within a streamlined housing 6 situated within a down-flow duct 7 and mounted by thin, vertical arms 8 through which extend the electrical circuits (not shown) to drive the motor. The air velocity may be varied by changing the propeller pitch.

The entire air ow is, in this embodiment, coniiued in a recirculating system which may include a lower section 9, the riser duct 1, and an upper section 10, joined by rounded bends containing directional guide vanes 11 to straighten and smooth the flow of air or reduce turbulence, thereby to keep the power requirements as low as possible. However, the invention is not restricted to a loop having four straight sections, and any upright loop may be used. The ducts 1, 7, 9 and 10 may have any desired cross section, e.g., circular, ellipsoidal or square. When the section containing the propellers 4 and -5 is not circular it is desirable to provide Cowling about the blades, as is indicated at 12. Such cowling smooths out the air flow and further is a safety means for protecting againgt loss of a propeller blade.

Although a simple embodiment of the means for supplying and discharging air is shown, it will be understood that any suitable air-flow system can be substituted and that recirculation of air is not essential (except probably in -terms of operating cost). Systems for the propulsion of air is well known in wind tunnels and may, for example, utilize so-called capillary systems, in which the recirculated air is flowed through a plurality of smaller ducts arranged in parallel, each having a fan. Also not shown, =but well known, are means for admitting air into and discharging excess air from the air system which consists of the ducts 1, 7, 9 and 10, and means for controlling the velocity of the air by adjusting the speed of the electric motor and/ or the pitch of the blades 4 and 5.

The air propulsion system must have the capability of flowing air upwards through the duct 1 at a velocity approximating the free fall velocity of a person in still air of the' same density. This velocity will depend upon the size and density of the person (as will be considered hereinafter) and the density of the ascending air; it is typically about 1Z0 miles per hour. For example, when the duct has a height of 30 feet between the nets 2 and 3 and is round in cross section with a width of 20 feet, the motor should have a capacity of about 1,000 to 2,000 horsepower.

The duct 1 has an upper access opening below the upper screen 3, which may lbe closed by a gate or door 15, leading to a closed entry room having a floor 16. This iloor forms a ledge from which a person can enter the duct 1 near the top. The room has a second door 17, whereby flow of air from the duct 1 through the opening to the outside is prevented. It is desirable to provide at least one such door although two doors or a double-door entry, in the nature of an air lock, is desirable. Outside of the door 17 are a platform 18 and a stairway 19. Au exit opening is formed at the bottom of the duct, just above the lower screen 2, which may also be closed by a door 20, leading into a room 21 having a rear door 22. All doors, or gates preferably are self-closing, e.g., have pneumatic or spring closing devices (not shown) and at least the door 20 can be opened from within the duct by merely pushing it into the room 21 and/or lby having a handle (not shown) for unlatching it from within the duct 1. All doors should swing in the direction of passage. Thus, the top door or gates swing toward or into the duct 1 and the lower doors swing away from the duct.

It may be noted that the pressure of the air within the duct 1 at one of the openings will assume the same pressure as the outside air when only that opening is left open, so that double doors or air locks will not always be required at both levels.

Either at the platform 18 or at the base of the stairway 19 may be provided a station for issuing suitable equipment to the person who is to use the apparatus. This being not a part of the invention, is not shown herein. Such equipment may include a helmet and jump suit, which may be a mere full-length cover or be enlarged by padding, e.g., of loose ber or foam resin wadding to reduce the chance of injury and/ or to reduce the density of the person and cause a reduced terminal free-fall velocity. This equipment may, of course, also include other paraphernalia such as ilaps or parachutes.

It is desirable to limit the number of occupants of the duct 1, e.g., to one person. For this purpose there is provided in the access room a light 23 which indicates occupancy of the duct. This light is extinguished by a controller, such as a stepping switch, which is not shown, being not a part of the invention and being known in various arts. In essence, this switch keeps the light extinguished after the door 15 has been opened until the door 22 has been opened and again shut, optionally further requiring the door 20 to be opened and shut.

In operation, when the electric motor is in operation and the fan Iblades 4, 5, circulate air and circulate air with the requisite upward velocity, the person opens the door 15 and enters the duct 1. By assuming various attitudes and/ or moving his limbs, clothing, or other equipment, he can vary the relative velocity between himself and the ascending air, falling slowly to the net 2, or hovering, or even -being carried upwards. The nets limit his movement.

Upon reaching the lower net 2 the person leaves the duct by opening the door 20, closing it after him, and then leaving via the door 22, which he again closes to signal the next person on the floor 16.

It is evident that when the clothing worn by the person increases his bulk and reduces his density the upward air velocity necessary to equal his free-fall velocity is reduced, thereby making it possible to use a smaller and less powerful fan.

I claim:

1. Apparatus for simulating the free fall of a person through air which comprises:

(a) a vertical confined air-flow duct, means for admitting air into the lower end of the duct for upward ow therethrough at a velocity approximately that of the terminal free-fall velocity of a person through still air of the density of said air in the duct,

4 and means for discharging said air from the top of said duct,

(b) lower guard means at the bottom and upper guard means at the top of said duct for restraining the passage of a person downwardly and upwardly from said duct,

(c) an access opening means in said duct situated between said guard means for admitting a person into and removing a person from the duct.

2. Apparatus according to claim 1, wherein said lower guard `means are situated above the bottom of the duct and the upper guard means are situated below the top of the duct, each of said guard means extending transversely across the duct and having openings for the passage therethrough of said air.

3. Apparatus according to claim 2 wherein said guard means are open-mesh screens.

4. Apparatus according to claim 2 wherein said guard means are nets of elastic material, said nets having large meshes.

5. Apparatus according to claim 1 wherein said access opening means includes a ledge situated at an upper part of said duct, said ledge for-ming a oor for supporting said person.

6. Apparatus according to claim 5 which includes wall structure enclosing the space above said ledge forming a closed room and a door for said room situated away from said duct for preventing air flow between the duct and the outside through said room. Y 7. Apparatus according to claim 1 wherein said access opening means includes two vertically spaced openings to said duct.

8. Apparatus according to claim 7 wherein each of said openings is provided with doors for preventing air flow between the duct and the outside through said openings.

References Cited UNITED STATES PATENTS 1,731,554 10/1929 Wheeler 73-148 2,229,201 l/ 1941 Williford et al 272--6 2,930,145 3/1960 Green 35-29 3,017,769 1/1962 Orlin 73-147 EUGENE R. CAPOZIO, Primary Examiner PAUL V. WILLIAMS, Assistant Examiner U.S. Cl. X.R. 73-147; 272--6 

